Effects of dexmedetomidine on early cognitive function in elderly patients after abdominal surgery: a meta-analysis.

INTRODUCTION: This meta-analysis aims to investigate the effect of dexmedetomidine (Dex) on postoperative cognitive dysfunction (POCD) in elderly patients undergoing abdominal surgery under general anesthesia. EVIDENCE ACQUISITION: Six online databases were searched for studies on the effects of Dex on POCD in elderly patients (≥60 years) who underwent abdominal surgery under general anesthesia. The experimental group was treated with Dex and the control group with normal saline. The retrieval period was from the database's inception to March 2023. Stata 15.0 statistical software was utilized to analyze the data. EVIDENCE SYNTHESIS: In total, 14 studies were entered into this meta-analysis, including 675 patients. On the first, third, and seventh days after surgery, the Mini-Mental State Examination (MMSE) scores in the experimental group were significantly higher than those in the controls (first day: weighted mean difference [WMD] = 2.52, 95% CI: 1.13~3.90, P<0.001; third day: WMD=2.58, 95% CI: 0.76~4.40, P=0.005; seventh day: WMD=1.43, 95% CI: 0.57~2.29, P=0.001). On the first day after surgery, there was a lot less cognitive dysfunction in the Dex group than in the controls (odds ratio [OR] = 0.25, 95% CI: 0.15~0.42, P<0.001). CONCLUSIONS: Dex administered intraoperatively can enhance early cognitive function in elderly patients undergoing abdominal surgery.

Effect of dexmedetomidine on hemodynamics in patients undergoing hysterectomy: a meta-analysis and systematic review.

OBJECTIVE: We conducted a meta-analysis and systematic review to evaluate the effects of dexmedetomidine on the hemodynamics of patients undergoing hysterectomy. METHODS: We searched the Medline, Embase, and Cochrane Central Register of Controlled Trials databases for clinical randomized controlled trials (RCTs) that allowed direct or indirect comparisons of hemodynamic indicators. We also searched nine English-language databases up to April 2021 to identify relevant research. The Cochrane risk-of-bias tool for RCTs was applied to assess the methodological quality of the eligible studies. The meta-analysis was conducted using RevMan 5.4 software. RESULTS: Nine trials were included in this systematic review. The effect of dexmedetomidine on heart rate during surgery was significantly smaller than that of other sedatives. Intraoperative systolic and diastolic blood pressure and mean arterial pressure were more stable in the dexmedetomidine group compared with the control group. The postoperative modified Observer's Assessment of Alertness Score was also better in the dexmedetomidine compared with the control group. CONCLUSIONS: Dexmedetomidine increases hemodynamic stability in patients undergoing hysterectomy, reduces the cardiovascular stress response during surgery, and effectively prevents postoperative adverse reactions, with good safety.

Antinociceptive effects of dezocine on complete Freund's adjuvant-induced inflammatory pain in rats.

Inflammatory pain is known to severely impact the life quality of patients. Notably, dezocine is widely used for the treatment of pain. Therefore, the current study aimed to examine the effects of dezocine on a complete Freund's adjuvant (CFA)-induced inflammatory pain model in rats and to investigate the possible underlying molecular mechanisms. Rats were randomly divided into three groups, including the control, CFA and dezocine+CFA groups, and then subcutaneously injected with 100 µl saline, subcutaneously injected with 100 µl CFA or pretreated with 1 ml dezocine (0.4 µg/kg) at 30 min before CFA injection in the plantar surface of right hind paw, respectively. The paw withdrawal threshold (PWT) and paw withdrawal latency (PWL) were measured with a dynamic plantar esthesiometer at 1 day before and 6 h after CFA injection. The ipsilateral lumbar spinal cords of all the rats were harvested for detecting the expression profiles of phosphorylated (p)-p65, p-extracellular signal-regulated kinase 1/2 (p-ERK1/2), cyclooxygenase-2 (COX-2), interleukin (IL)-1ß and tumor necrosis factor (TNF)-α by western blot analysis and/or reverse transcription-quantitative polymerase chain reaction. In addition, prostaglandin E2 (PGE2) expression was determined by enzyme-linked immunosorbent assay. Compared with the control group, CFA-induced peripheral inflammation downregulated the PWT and PWL values of rats, which were significantly alleviated by dezocine treatment. Furthermore, the protein levels of p-p65, p-ERK1/2, COX-2, PGE2, IL-1ß and TNF-α were significantly upregulated following CFA injection, while they were suppressed by dezocine pretreatment. In conclusion, the analgesic effect of dezocine on inflammatory pain induced by CFA may be associated with the inhibition of the spinal ERK1/2-COX-2 pathway.

[Effects of tanycytes transplantation on the motor function score and rubrospinal motor evoked potentials of adult rats after spinal cord completely transected].

OBJECTIVE: To determine whether tanycytes be able to support the regeneration of completely transected spinal cord in adult rats. METHODS: Subcultured tanycytes was transplanted into completely T8 transected spinal cord using the untranslated completely transected rats as control. After transplantation the rubrospinal motor evoked potentials were recorded below the injury level at the end of 12th week, assistant by Basso-Beatie-Bresnahan locomotor rating scale and histology method. RESULTS: At the end of 12th week the total peak amplitude of rubrospinal motor evoked potentials (MD = 133.2 microV, P < 0.01) and BBB locomotor rating scale (MD = 5.0000, P < 0.01) were both significantly improved in cell transplanted group compared with that in the untranslated control group, while the latency of the first peak was shortened (MD = 0.061 ms, P = 0.040). HE staining showed more integrity in transected spinal cords in cells transplanted groups. CONCLUSION: Transplanted tanycytes can support the regeneration of transected spinal cords in rats.

[Relationship between graded spinal cord injury and rubrospinal MEPs in rats].

AIM: To explore an accurate neurophysiological technique that demonstrates small functional differences after spinal cord injury and assesses therapeutic interventions. METHODS: A modified weight drop (WD) technique was used at T8 in rats to build graded spinal cord injury model. Rubrospinal MEPs were recorded at T13 epidurally to monitor spinal cord function in end week 4 after graded spinal cord injury. The efficacy of this techniques to monitor spinal cord function was compared to BBB locomotor rating scale and histologic evaluation. RESULTS: A characteristic peak complex of rubrospinal MEPs in sham-operated group consisted of 5-7 positive waves and 4-5 negative waves emerging after red nucleus stimulation. The summed peak to peak amplitude (for practical reasons, called peak amplitude) was (195.25 +/- 34.35) microV and decreased following spinal cord injury. The latency of the first peak (positive wave) was (1.57 +/- 0.15) ms and prolonged following spinal cord injury. Significant Linear relationship existed between the peak amplitude and the BBB scores (r = 0.79) and between the peak amplitude and the residual matter obtained from the section with maximum tissue damage( r = 0.87). The close relationship between the latency of the first peak and the BBB scores (r = -0.88) and between the latency of the first peak and residual matter (r = -0.86) were observed. CONCLUSION: Amplitudes and latencies of rubrospinal MEPs are very valuable parameters to demonstrate small function differences. Rubrospinal MEPs can be used as a reliable measure for motor function prognosis after spinal cord injury.

[Excitatory postsynaptic potential evoked by stimulation of the ventrolateral region of the cerebellum in crucian carp Mauthner cell].

In the present experiments, the characteristics of the electrical responses to stimulation of the cerebellum in crucian carp Mauthner cell were explored with microeletrode intracellular recording technique. A composite excitatory postsynaptic potential (cerebellum-evoked EPSP) could be induced from the soma, the ventral dendrite and the proximal end of the lateral dendrite in crucian carp Mauthner cell (M-cell) on either side by stimulation of the ventrolateral region of the cerebellum. The cerebellum-evoked EPSP presented characteristics of relatively short latency (0.63+/-0.09 ms), longer duration (5.49+/-1.13 ms), graded amplitude and dependence on stimulation frequency. Stimulation of the cerebellum with higher intensity always activated the M-cell orthodromically. Multiple intracellular recordings showed that the cerebellum-evoked EPSP originated in the distal end of the ventral dendrite. The results suggest that the cerebellum-M-cell pathway is probably composed of a group of neuron chains with different numbers of synaptic relays projecting to the distal end of the ventral dendrite in order of length of the chains.